Emerging information-centric networking architectures are currently changing the landscape of network research. In particular, named data networking (NDN), or content-centric networking (CCN), is a proposed network architecture for the Internet that replaces the traditional client-server model of communications with one based on the identity of data or content. This architecture more accurately reflects how the Internet is primarily used today: instead of being concerned about communicating with specific nodes, end users are mainly interested in obtaining the data they want. The NDN architecture offers a number of important advantages in decreasing network congestion and delays, and in enhancing network performance in dynamic, intermittent, and unreliable mobile wireless environments.
Content delivery in named data networking (NDN) is accomplished using two types of packets and specific data structures in nodes. Communication is initiated by the data consumer or requester. To receive data, the requester sends out an Interest Packet (also called an “interest”), which carries the (hierarchically structured) name of the desired data (e.g. /contentsourcey/videos/WidgetA.mpg/1). The Interest Packet is forwarded by looking up the data name in the Forwarding Information Base (FIB) at each router the Interest Packet traverses along routes determined by a name-based routing protocol. The FIB tells the router to which neighbor node(s) to transmit each Interest Packet. Each router maintains a Pending Interest Table (PIT), which records all Interest Packets currently awaiting matching data. Each PIT entry contains the name of the interest and the set of node interfaces from which the Interest Packets for the same name arrived. When multiple interests for the same name are received, only the first is sent toward the data source. When a node receives an interest that it can fulfill with matching data, it creates a Data Packet containing the data name, the data content, together with a signature by the producer's key. The Data Packet follows in reverse the path taken by the corresponding Interest Packet, as recorded by the PIT state at each router traversed. When the Data Packet arrives at a router, the router locates the matching PIT entry, transmits the data on all interfaces listed in the PIT entry, and then removes the PIT entry. The router may optionally cache a copy of the received Data Packet in its local Content Store, in order to satisfy possible future requests. Consequently, a request for a data object can be fulfilled not only by the content source but also by any node with a copy of that object in its cache.